M. Baudinet, J. Chomicki, and P. Wolper. Constraint-generating dependencies. Journal of Computer and System Sciences, 59, 1999.  Home/Search   Document Details and Download   Summary   Related Articles   Check

....two attributes birth year and recruitment year, then we certainly want to enforce that, for all instances of Employee, the value of birth year is smaller than the value of recruitment year. Such attribute dependencies for relational databases are well known and have been investigated in, e.g. [8, 3, 16]. However, research about this topic has focussed on the consistency and implication problems for sets of attribute dependencies. If reasoning about ER schemas (translated into an appropriate DL) is used to infer properties of the conceptual model, it seems more appropriate to strive for an ....

M. Baudinet, J. Chomicki, and P. Wolper. Constraint-generating dependencies. Journal of Computer and System Sciences, 59, 1999.

....concludes the proof. 2 4.3 Complexity The following theorem considers the complexity of the logical implication problem for TDs. Theorem 2 The logical implication problem for TDs is coNP hard. Proof. TDs encompass typed clausal constraint generating 2 dependencies, proposed by Baudinet et al. [5]. The logical implication problem is coNP complete for this type of dependencies [5, theorem 10] This concludes the proof. 2 As an immediate corollary of Theorem 1 and Theorem 2, TDSAT is NP hard. We now explore an upper bound for the complexity of a given TDSAT problem (U; Sigma; ff) As one ....

....( but also for order (f ; g) Inequality (6= is not considered. The order is not required to be total. The major contribution of TDs compared with order dependencies is the explicit modeling of the time dimension in TDs. Constraint generating dependencies proposed by Baudinet et al. [5] generalize equality generating dependencies, which subsume FDs, by replacing equality requirements by constraints on an interpreted domain. A special type of constraint generating dependency fixes the language of constraint formulas to equality ( inequality (6= and order ( constraints. ....

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M. Baudinet, J. Chomicki, and P. Wolper. Constraint-generating dependencies. In Proc. 5th Int. Conf. on Database Theory, LNCS 893, pages 322--337. Springer-Verlag, 1995.

....c semantic restrictions which, in traditional database systems, are represented as integrity constraints. One of the widest class of integrity constraints is the constrained tuple generating dependencies (CTGDs) 1] which generalize traditional dependencies such as FDs, MVDs, EGDs, TGDs[2] and CGDs[3]. Here, we further extend this class to allow disjunctions. We call the resulting This work was partly supported by the Australian Research Council. class of integrity constraints disjunctive constrained tuple generating dependencies (DCTGDs) Such dependencies are needed to represent a wide ....

....applications where the potential for improvement is much greater than in traditional databases. Two key problems are testing query containment and testing integrity constraint implication. Previous researchers have developed and studied techniques for proving implication of integrity constraints [1, 3, 5, 6], and have proposed techniques for query optimization [4, 7] We extend this previous work to handle DCTGDs as follows. In Section 2, we de ne our generalized classes of integrity constraints and queries. In Section 3, we present a procedure for expanding a query Q in the presence of a set of ....

M. Baudinet, J. Chomicki, and P. Wolper. Constraint-generating dependencies. Journal of Computer and System Sciences 59, 94-115, 1999.

....as Q = if its answer set is empty for all database instances. 2. 2 Integrity Constraints Common integrity constraints in a database can be expressed using data dependencies, such as functional dependencies, constraint generating dependencies (CGDs) tuple generating dependencies (TGDs) BCW99,FV] A more general data dependency, named Constraint Tuple Generating Dependency (CTGD) is studied in [MS] Formally, a CTGD is a formula of the form p 1 (X 1 ) pn (Xn ) C(X) 9 Y1 ; Y m q 1 (X 0 1 ; Y 1 ) q m (X 0 m ; Ym ) D(X;Y ) 1) where X = X 1 [ Xn ; Y = Y 1 [ ....

M. Baudinet, J. Chomicki, and P. Wolper. Constraint-generating dependencies. Journal of Computer and System Sciences 59, 94-115, 1999.

.... increases the flexibility of the integrity constraints, even when the data is purely relational (i.e. without constraints) Three classes of integrity constraints: functional dependencies, equality generating dependencies, and tuple generating dependencies have been extended with constraints [2,39,40]. The corresponding algorithms to test for implication of dependencies reduce to the usual algorithms when constraints are omitted. As above, the algorithms are also simplified when INC holds. 5.5 Non Monotonic Reasoning Although many default reasoning techniques (e.g. default logic [48] ....

M. Baudinet, J. Chomicki & P. Wolper, Constraint-Generating Dependencies, in G. Gottlob and M.Y. Vardi (Eds.), Database Theory -- ICDT'95, Lecture Notes in Computer Science 893, Springer-Verlag, 322--337, 1995.

....for these cases, modulo the cost of constraint manipulation. For domains where the problem appears intractable we provide tractable approximations. We have slightly weaker results for constrained finiteness dependencies. There is closely related work on constraint generating dependencies (CGDs) [4], a general class of dependencies which includes CFDs but not constrained finiteness dependencies. That paper provides an elegant reduction of the implication problem for CGDs to the validity problem of constraint formulas, but does not suggest an efficient algorithm for CFDs. Earlier work on ....

....direction is trivial. For the other direction, suppose that C; F 6j= f . Then there is a relation R, which can be chosen to have exactly two tuples, that satisfies C; F but not f . Since R is finite it also satisfies G. Thus C; F; G 6j= f . 2 23 8 Constraint Generating Dependencies In [4] the complexity of the implication problem is examined for a large range of dependencies, including constrained functional dependencies (but not the constrained finiteness dependencies) called constraint generating dependencies. Definition 8.1 A constraint generating dependency (CGD) takes the ....

[Article contains additional citation context not shown here]

M. Baudinet, J. Chomicki & P. Wolper, Constraint-Generating Dependencies, Proc. 5th International Conference on Database Theory, LNCS 893, 322--337, 1995.

....query containment Still on nite databases, another natural question we may ask is whether the classical problem of conjunctive query containment remains decidable when we now have a structure on our universe U. Given our basic assumption that the theory of U is decidable, the answer is yes [17, 3]. Of course conjunctive queries also make perfect sense on general constraint databases with in nite relations. Much less is known about containment testing in this setting, however. 17 Spatial databases as constraint databases Now some attention to type 2 research. Using the reals as our ....

M. Baudinet, J. Chomicki, and P. Wolper. Constraint-generating dependencies. Journal of Computer and System Sciences, 59(1):94{ 115, 1999.

....databases. Integrity constraints play an important part in regular relational database design and have been investigated in great detail (see [143] Dependency theory among integrity constraints for generalized databases is however a fairly open area, which was investigated only recently [15, 103]. 15] defines constraint generating dependencies and studies the computational complexity of their implication and consistency problems. Let emp(name; salary; boss) be a relation storing information about employees in a company. An example of a simple case of constraint generating dependency is ....

.... Integrity constraints play an important part in regular relational database design and have been investigated in great detail (see [143] Dependency theory among integrity constraints for generalized databases is however a fairly open area, which was investigated only recently [15, 103] [15] defines constraint generating dependencies and studies the computational complexity of their implication and consistency problems. Let emp(name; salary; boss) be a relation storing information about employees in a company. An example of a simple case of constraint generating dependency is 8n 1 ....

M. Baudinet, J. Chomicki, P. Wolper. Constraint-Generating Dependencies. Proc. 5th Int. Conf. on Database Theory, 322--337, 1995.

....approach of Jensen, Snodgrass and Soo is subsumed, generalized, and clarified by the classical approach [Chomicki, 1997] BRICS Mini course on Temporal Databases Valid time: t v , transaction time t t . Many examples in [Jensen and Snodgrass, 1994] Complexity results for the implication problem [Baudinet et al. 1995]. Not clear how to use CGDs for database design. Further generalizations: tuple generating constraint dependencies [Maher and Srivastava, 1996] 111 2 Constraint Dependencies Functional dependencies are equality generating. In temporal databases it is natural to consider more general ....

....for database design. Further generalizations: tuple generating constraint dependencies [Maher and Srivastava, 1996] 111 2 Constraint Dependencies Functional dependencies are equality generating. In temporal databases it is natural to consider more general constraint generating dependencies [Baudinet et al. 1995]. Example: The past never changes. 8x; x 0 ; t v ; t 0 v ; t t ; t 0 t : p(x; t v ; t t ) p(x 0 ; t 0 v ; t 0 t ) t v t 0 v ) t t t 0 t BRICS Mini course on Temporal Databases 112 2 Temporal ICs in Relational DBs Integrity constraints on histories. Examples: salaries ....

Baudinet, M., Chomicki, J., and Wolper, P. (1995). ConstraintGenerating Dependencies. In International Conference on Database Theory,

....evidence for or against the association. The TD s proposed in this paper compare attributes in one tuple with the corresponding attributes in another tuple. That is, TD satisfaction is expressed in terms of tuple pairs rather than individual tuples. Following the terminology of Baudinet et al. [BCW95], TD s are constraint generating 2 dependencies, whereas classical association rules are constraintgenerating 1 dependencies. Before we turn to the technical treatment, we mention that TD s can be easily extended to capture data regularities within a single state (called intrastate dependencies in ....

M. Baudinet, J. Chomicki, and P. Wolper. Constraint-generating dependencies. In Proc. 5th Int. Conf. on Database Theory, LNCS 893, pages 322--337. Springer-Verlag, 1995.

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M. Baudinet, J. Chomicki, and P. Wolper. Constraint-generating dependencies. Journal of Computer and System Sciences, 59, 1999.

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Marainne Baudinet, Jan Chomicki, and Pierre Wolper. Constraint-Generating Dependencies. In International Conference on Database Theory, 1995.

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Marainne Baudinet, Jan Chomicki, and Pierre Wolper. Constraint-Generating Dependencies. In International Conference on Database Theory, 1995.

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